Well, what can I say. I have and 2002 tribute that the battery light works the oppisite of how its supposed to work. The light should be on when the key is turned on, and go out when the correct voltage is reached. Note when started the light comes on but is very dim. You can only see on when its very dark. Strange issue. but system is charging fine and handles load ok. I think its just indication issue. Now its time to install amp gauge I suppose.

 

I am not clear on your description. Is the light dim only at the start or all the time once the car is running?

What is the voltage at the battery when the car is running?

 

Here's the problem. The battery/Alt light is on when you turn the key. Once the car is started the light should go out telling you that the alt output is good. The problem I have is when I turn the on, not start the light is already out. Possbile ground issue. not sur yet. When I start the car and its running the light is very dime and stays dime. You can only see it when its very dark. Ive just replaced the alt and it was that way prior. Not relizing it. The system works its just and indication problem so far. Im checking all grounds and shooting wires. Im thinking its the microprocessor in the instrument cluster. Any thoughts

 

I would make sure all of your fuses are good first that is the easiest thing to check. If all of your fuses are good then make sure the light green wire with the red tracer is not open. I cant find out what the voltage drop should be, I could not find that information on all data. But if you unplug that connector from the alternator, then unplug the cluster connector(c220c). Then you can check that circuit for resistance to see if it is open it should read about 0.02 ohms. So that will be pin 3 on the alternator connector and pin 16 on the cluster connector(c220c). If this wire is not open then it is most likely the cluster is bad as long as the alternator is but putting out the respectable voltage, but I cannot find that spec.

If this sounds to confusing to you I recommend taking it to a reputable repair shop.

 

I had my alt go out at about 80-90k miles on my 2003 Es. My warning was give in the form of the batt light blinking at full throttle acceleration. Maybe give that a shot...stomp on it when its safe to do so, and see if the light blinks.
-a